-------------------------------------------------------------------
THE RELATIVE MONTHLY MEAN SUNSPOT NUMBER ON APRIL 2021 HAS MADE 
              Wmar. = 14.7         24.5(n-in new system)  
THAT GIVES FOR 10 MONTH (2020, OCTOBER) OF DEVELOPMENT CURRENT 25 SOLAR 
CYCLE THE SMOOTHED MONTHLY MEAN SUNSPOT NUMBER 
              W*oct. = 7.1         11.9 - × ÎÏ×ÏÊ ÓÉÓÔÅÍÅ
              W*sep. = 6.2         10.3 - × ÎÏ×ÏÊ ÓÉÓÔÅÍÅ
 On July 1, 2015 Centre in Brussels moved to a new system of calcu-
lation the relative number of sunspots and practically all of the 
values were replaced throughout the numbered series of Wolf numbers 
(see link). While there is addictive, I recalculated (0.6) to the 
old system, but only W*, and present below the new values for the 
minimum and maximum of 25 cycles SA. 

THE BEGINNING OF 25 SOLAR CYCLE  -  I 2020  with W*=1.3; (1.8n)  
MAXIMUM OF THE CURRENT 25 CYCLE  - VI 2024 - Wmax =90-100; (150n)
THE END OF 25 SOLAR CYCLE (THE POINT OF MINIMUM) -  I - VI 2031;

Provisional daily International Sunspot Numbers for February 2021 
(èè observatories): 
                    NO DATA on http://sidc.oma.be/
[The daily value W in old system close to true (in a minimum phase) 
can be received, multiplying by k = 0.6].
 
THE MONTHLY MEAN OF OBSERVED RADIO FLUX OF THE 10 cm (2800 MHz) ON 
APRIL 2021, AND SMOOTHES ON 2020, OCTOBER
               F10.7apr. = 74.5           F*10.7oct.= 75.2 

THE MONTHLY MEAN OF GEOMAGNETIC Ap-index ON APRIL 2021, 
AND SMOOTHES ON 2021, OCTOBER 2020
               Ap apr.= 8.6               Ap*oct. = xxx
---------------------------------------------------------------------
       Weekly Bulletin on Solar and Geomagnetic Activity
                  Highlights on 26.4 - 02.05.2021,
                   Forecast on 03 - 10.05.2021,
              Carrington Rotation 2243 (11,47.05.2021)   
             Earth out of ecliptic (-5.0 - -4.6) deg. 
             (S35 - N25 is zone of geoeffectiveness)

THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON LOW LEVEL AND
02.05 THE SUN WAS SPOTLESS (42 DAYS AT 2021). ESTIMATED, MOST 
LIKELY  WEEKLY AVERAGE VALUE OF THE SUNSPOT NUMBER  IN THE IN-
TERNATIONAL SYSTEM (old) FOR PERIOD W=24+14/-24 (Wn=34+30/-34). 
THREE SMALL SUNSPOT GROUPS WERE OBSERVED ON THE SOLAR VISIBLE 
DISK WICH FORMED A COMPLEX OF ACTIVE REGIONS.

 NEXT WEEK SUNSPOT ACTIVITY  WILL BE ON VERY LOW LEVEL. WEEKLY 
AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATI-
ONAL SYSTEM (old) FOR NEXT WEEK IS W=010+20/-10. 

 FLARE ACTIVITY WAS AT LOW LEVELS. ONE SOLAR FLARE "ó" OF X-RAY 
CLASS, 37-CLASS "B", TWO SOLAR FILAMENT ERUPTIONS AND 8 CORONAL 
MASS EJECTIONS (26, 29-30.04, 2.05) WAS OBSERVED. 
-------------------------------------------------------------------
FLARES >M1 X-RAY CLASSES
       to   tm   te     local.   Class   E(1-8A) AR  RII/IV   CME
                                X-ray/Ïp  J/m-2
19.04 2319	2342	2359	S24E23L264 M1.1  1.3å-2 12816 II/IV   óíå                               
DSF     to     te   localization   l deg.  Fl    AR    CME/to
26.04       1635     S55W14L174     >10
29.04       1613     N55E65L214     >15               CME/ 
--------------------------------------------------------------------
NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT VERY LOW LEVEL.

ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED:
---------------------------------------------------------------------
  sign  N end   E end   S end   W end  Sch   EE     R G  Sp/craft 
CH* +  N10L230 S05L235 S12L225 N09L219 ~5%   29.04 >5  -  SOHO,SDO...
* - low geoeffectivity, the substorms with duration <6 h. only.
Sch - CH area in % solar hemisphere near the central meridian on 
https://www.solarmonitor.org/; n/d - no data; R - solar rotations; 
EE-date of possible geomagnetic disturbance in the Earth's environment. 
G(0-5)-geoeffectivity in last solar rotation on the middle latitudes. 
A-active geomagnetic condition. 
----------------------------------------------------------------------

 AFTER 29.04/1325 UT THE EARTH IS IN THE "-" SECTOR OF THE INTERPLA-
NETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE 
EXPECT 8.05.
---------------------------------------------------------------------- 
APRIL    26     27     28     29     30     01     02   íáê
Wus     064    047    042    037    035    011    000
F10.7   080    079    078    077    073    072    072    
èbcg   á7.1   á7.4   á6.6   á5.6   á4.5   á3.1   A3.0   GOES
Sp      220    140    070    070    070    010    000   msh   
N                                                      
IMF      -      -      -     -/+      +     +      +    DSCOVR   
Å>2  2.9E+6 1.4å+8 4.1E+7 4.6E+7 4.3E+7 8.9å+6 2.1E+6   GOES
Ie>2    351    541   1063   1076   1836    385    262   pfu
Ap       14      8     3      6      6      5      10   nô  
Dst                                                     nô KIOTO
Amsc     13      6     2      4      7      6      11   nô IZMIRAN
----------------------------------------------------------------------            
Å>2 - Daily Electron Fluency e/(cm2-ster-day) with E>2 MeV.
Ie>2 - the maximum intensity of electron flux in geostationary or-
bits in days according to GOES-15 in (electrons/cm2.s.sr) for events
> 1000 pfu.

THE GREATER THAN 2 MeV RECURRENT ELECTRON FLUX AT GEOSYNCHRONOUS 
ORBIT BEGUN 30.04/1530 UT AND WAS OBSERVED 28-30.04. 
 
NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS 
ORBIT IS NOT EXPECTED.

GEOMAGNETIC CONDITION VARY FROM UNSETTLTD TO QUITE. 

IN THE NEXT WEEK THE MOST PROBABLE IS EXPECTED A QUITE AND UNSET-
TLED GEOMAGNETIC CONDITION. 

HIGHLIGHT AND FORECAST COMPOSED FROM DATA:
NOAA SWPC, BOULDER, USA               http://www.swpc.noaa.gov,
THE SOLAR INFLUENCES DATA ANALYSIS CENTRE, 
SIDC, BRUSSELS, BELGIUM               http://sidc.oma.be/index.php3, 
THE IZMIRAN, MOSCOW, TROITSK, RUSSIA  http://www.izmiran.ru
                                                          V. Ishkov